Oh, it will work, no doubt, just at less than the ideal speed. Such a minimalist program was espoused by Mike Mentzer, one of the great bodybuilders of past decades. But his views are not considered mainstream.

I agree that a full 24 ... 25 reps (3x8, 8x3, 5x5, etc.) program is not required for maintenance only.

To get into shape... well, I guess it depends on the temperament. I'm inclined to achieve the goal as quickly as possible, then focus on something else. Hence my previous reply.